Bicycles have been around since the early 1800s. The design of the bicycle is continuously being improved, increasing its efficiency in various aspects. The result is that today we have sleek, lightweight and fast bicycles which are capable of efficiently transferring the energy from the cyclist's legs to the wheels of the bicycle.
Cyclists have many different bicycle styles to choose from, each with their own advantages and disadvantages. However, there are generally two positions used for road cycling, a more upright position as seen when using road bikes, hybrids and mountain bikes, and a more aerodynamic, forward leaning position as seen on time-trial or triathlon bicycles. Cycling enthusiasts frequently desire the advantages of both riding positions. For example, an aerodynamic, forward leaning position is often desirable at higher speeds, when a rider is seeking to minimize wind resistance. The more upright position is often preferred on road bicycles when the rider is climbing hills, maneuvering within a group of riders, or maximizing comfort.
One of the big differences in design on bicycles with these two different styles of riding is the seat (aka “saddle”) position. Specialized bicycles, such as those designed for triathlons or time trials, have steeper seat tube angles that place the saddle further forward relative to the bottom bracket. This allows the rider to assume a more aerodynamic position where arms are extended further forward onto cantilevered aero bars and shoulders are lowered, thus reducing a rider's frontal area and creating a more aerodynamic shape. Clip-on aero bar extensions have been developed for road bicycles to allow riders to achieve a similar aerodynamic position, but their use puts the rider in an uncomfortably stretched out position due to the limited forward travel adjustment of the typical seat. Another problem can occur when lowering the torso to assume an aerodynamic position: For a rider bending down and forward into aerobars without adjusting the saddle position, the rider's hip-angle (the angle between the rider's torso and upper leg at the top of the pedal stroke) can become cramped and uncomfortable.
Road bicycle seat posts typically allow adjustment to the height, tilt, and fore-aft position of the saddle within a limited range. However, if a road bicycle cyclist desires to have a more aerodynamic position, he requires specialized seat posts to place the saddle in a significantly further forward position. Once installed, the seat post does not allow the seat to be moved back to a position that would be suitable for normal upright road riding without reinstalling the traditionally positioned seat post.
Likewise, typical saddles assemblies require adjusting the tilt or “seat angle” by loosening a bolt, physically manipulating the position of the saddle to the desired seat angle or tilt, then tightening the bolt to hold the saddle in fixed position. For a rider wanting to change riding styles during a ride, changing the seat angle requires getting off the bicycle to perform these adjustments. For a rider wanting to frequently alternate between two riding styles, there is no way to rapidly, easily, and reliably switch between two reliably consistent seat angles.
The traditional saddle position on a road bike can be uncomfortable when using aero bars and the forward saddle position used with aero bars is not suitable when conditions call for a more traditional upright road position. Switching seat posts is time consuming, may require the use of tools, and typically cannot be done in the middle of a ride. There is thus a need for a means to easily adjust the saddle position during a ride that does not require the use of tools or the replacement of a seat post.